Process of producing isoprene.



lllhlll il lfllh @ltdliliidhl GEOBG MERLING- AND HUGO KGHLER, OFELBER-FELD, GERMANY, ASSIGNORS TO FAR- BENFABEIKEN VORJVL FRIEDR. BAYER& 00., 0F ELBERFELD, GERMANY, A COR- 'PORATION 0F GERMANY.

PROCESS OF PRODUCING- ISOPRENE.

No Drawing.

halogen halogen In order to illustrate the new process more fully thefollowing examples are given, the parts being by weight:

Example 1-Manufactm e anal production of isopreae from thetetra-ammom'um-ahloreel CH3CHCH(CH )-CH2OH CH3 N CH3 Cl CH3 1 part ofthe ammonium chlorid which can be easily obtained according to the wellknown methods and which is a colorless, deliquescent crystal mass m isdissolved in about 5 parts of water. Thesolution while being cooled withice is saturated with hydrobromic acid and is heated for 2lhours in anautoclave in a boiling water bath. When the solution is evaporated onthe water bath or after the water and the superfluous hydrob-romic acidis separated in another suitable manner the bromin ammonium chlorid I CHT CH3 Specification of Letters Patent.

. tion is evaporated on Patented ll'lill. 25, 1913.

Application filed December s, 1911. Serial No. 664,137.

syrup is distilled with about three times its quantity of pulverizedcaustic potash or caustic soda or with calcium or barium hydroxid withor without the addition of alcohol or water. lhe isoprene distils over.

It is collected in a receiver cooled with ice,

separated from the trimethylamin by wasl1- ing it with diluted sulfuricacid, dried and distilled. lt'boils constantly at from 3435 C. The yieldis nearly a theoretical one. The same result can be obtained bysaturating the aqueous solution of 1 part of the above mentionedoxyammonium chlorid in 5 to 6 parts of water with hydrochloric acid at atemperature of about 0 0.; the solution'is heated for '24: to 48 hoursto from 1201.30 C. andafter being cooled a dark resinous substance isfiltered ofi and the filtrate evaporated on the water bath. Thechloro-ammonium-chlorid CH CH-CH(CH )-CHz.Cl

remains as a viscous brown syrup which when heated with concentratedalkali lye or with pulverized caustic potash Or with calcium orbariumhydroxid is decomposed into hydrochloric acid, trimethylamin andisoprene which latter is separated and purified as above mentioned. I

E mamp'le 2Manufacture and production of isoprene from the tetra-ommwmumchlo- The ammonium chlorid which can be obtained by directly combiningthe oxy base:

with methyl chlorid or by converting the ammonium iodid thereof (meltingpoint 145146 G.) with silver chlorid is a colorless,- deliquescentcrystal mass. It is dissolved in about 5 parts'of water and the wellcooled solution is saturated with hydrobromic acid or hydrochloric acid,and heated in an autoclave on'the boiling water bath for about 24 hours.When the clear solutlmwater bath or the water and the superfluoushydrogen halid is separated in another suitable manner, the bromoo-rchloro-ammonium chlorid:

remains as a thick brown syrup, which is distilled with about threetimes its quantity of pulverized caustic potash or soda or also withcalcium or barium hydroxid with or without the addition of alcohol orwater. The isoprene distils over, it is collected in a tube, cooled withice, separated from trimethylamin by washing it with diluted sulfuricacid, dried and distilled. It boils constantly at 34 C. The yield isnearly theoretical.

We claim 1. The process of producing isoprene from a halogen ammoniumhalogenid containing the following graphically. represented nucleus:

which comprises heating such halogenid With an alkali.

2. The process for producing isoprene,

which process consists in first heating with an alkali ahalogen-ammonium halogenid having the hydrocarbon radical:

c'n ca-dn-cur and secondly isolating the isoprene from the resultingmixture, substantially as described. In testimony whereof we havehereunto set our hands in the presence of two subscribing witnesses.

GEORG MERLING. [L. s.] HUGO KOHLER. [1,. s.] Witnesses: v

HELEN NUFER, A. NUFER.

